Data transmission method, device and system for unmanned aerial vehicle communication

Abstract

This invention provides a data transmission method, apparatus, and system for unmanned aerial vehicle (UAV) communication. The method includes: dividing a transmission frame containing M consecutive time slots into: the first M-1 time slots as communication time slots, and the Mth time slot as a channel scanning time slot. Within the communication time slot, the UAV communication device performs bidirectional data transmission on the current operating channel k. Within the channel scanning time slot, the operating channel of the UAV communication device is switched to the scanning channel p, and channel feature scanning is performed on the scanning channel p; wherein the scanning channel p changes with the frame number, and one channel is scanned in each frame, cyclically traversing from 1 to N, where N is the total number of selectable channels. Based on the scanning information obtained from scanning all N channels in N consecutive transmission frames, the communication quality and link occupancy status of each channel are evaluated. Based on the evaluation results, a target channel is determined, and the operating channel is switched to the target channel.

Description

Technical Field

[0001] This invention relates to the field of communications, and particularly to data transmission methods, apparatus and systems for unmanned aerial vehicle (UAV) communications. Background Technology

[0002] In the field of drone communication, existing wireless data transmission systems mainly rely on the following technical solutions: public cellular networks (2G / 3G / 4G / 5G), Wi-Fi, one-way broadcast links, narrowband frequency hopping / spread spectrum data transmission, frequency division duplex (FDD) bidirectional links, and time division duplex (TDD) bidirectional links. However, the above solutions all exhibit varying degrees of limitations and shortcomings when facing drone swarm operation scenarios, specifically manifested as follows: Public cellular networks: Their performance heavily relies on the coverage density of operator base stations, often resulting in no signal or weak signal in mountainous areas, at sea, disaster sites, or military mission areas. Furthermore, public network links cannot provide deterministic low latency, making it difficult to meet the high reliability requirements of real-time UAV flight control. Wi-Fi: In environments with severe multipath fading, such as suburbs, forests, and urban canyons, link packet loss rates are high and communication distances are short. Moreover, the Wi-Fi protocol stack is primarily best-effort, lacking a Quality of Service (QoS) guarantee mechanism, making it unable to stably transmit high-definition images or perform precise telemetry and remote control. One-way broadcast links: These can only complete one-way command injection from the ground station to the UAV. Status, telemetry, and image data from the UAV require an additional reverse link for backhaul, leading to a complex system architecture, low spectrum utilization, and difficulties in synchronizing bidirectional links. Narrowband frequency hopping / spread spectrum data transmission: While enabling long-distance, low-power remote control and telemetry under low signal-to-noise ratio conditions, its limited data bandwidth (typically below 100 kbps) cannot meet the needs of real-time high-definition or even ultra-high-definition video backhaul, and can only serve as an emergency backup link.

[0003] FDD bidirectional links occupy independent frequency bands for both uplink and downlink, allowing uplink and downlink to operate simultaneously. This offers advantages such as low latency, high real-time performance, and the elimination of synchronization requirements for bidirectional links, effectively mitigating the problems associated with the aforementioned transmission methods. However, when the frequency interval between the two frequency bands in an FDD bidirectional link is small, local oscillator leakage and intermodulation products at the airborne or ground-based end will cause severe self-interference, leading to decreased receiver sensitivity and deterioration of the link budget. Furthermore, the FDD architecture requires two sets of RF front-ends (PA, LNA, filters, antennas, etc.), significantly increasing hardware cost, size, and weight, which is detrimental to the miniaturization and weight reduction of UAV platforms.

[0004] TDD (Time Division Duplex) bidirectional links achieve bidirectional transmission on a single frequency point through time division multiplexing, avoiding the self-interference problem in FDD (Frequency Division Duplex). However, in multi-drone collaborative operation scenarios (such as emergency search and rescue, agricultural plant protection, and security patrol), each drone typically needs to use an independent wireless communication system. The transmission signal of any drone can cause adjacent channel interference to the reception of other drones, leading to problems such as spectrum conflicts and network congestion. This will reduce the throughput of surrounding networks, increase control command delays and jitter, and ultimately affect the communication reliability of the overall drone system. In addition, drone operations generally exhibit typical "uplink and downlink service asymmetry" characteristics. The downlink only needs to transmit low-bit-rate remote control commands (tens to hundreds of bps), while the uplink needs to transmit high-bit-rate multiple high-definition video streams and a large amount of sensor data (several Mbps to tens of Mbps). Existing symmetrical or quasi-symmetrical communication systems cannot dynamically optimize resources for this service characteristic, resulting in low spectrum efficiency. Summary of the Invention

[0005] In order to overcome at least one deficiency of the prior art, the present invention provides a data transmission method, apparatus and system for unmanned aerial vehicle (UAV) communication.

[0006] To achieve the above objectives, a first aspect of the present invention provides a data transmission method for unmanned aerial vehicle (UAV) communication, applicable to a transmission system comprising one or more UAV communication devices, each UAV communication device being configured with a master end and a corresponding slave end. The method includes: The transmission frame containing M consecutive time slots is divided into: the first M-1 time slots are used as communication time slots, and the Mth time slot is used as a channel scanning time slot; within the communication time slot, the UAV communication device performs bidirectional data transmission on the current working channel k, where k is an integer between 1 and N, and N represents the total number of selectable channels in the system; During the channel scanning time slot, the working channel of the UAV communication device is switched to the scanning channel p and the channel feature is scanned on the scanning channel p; wherein, the scanning channel p changes with the frame number of the transmission frame, and one channel is scanned in each frame to cyclically traverse from 1 to N; Based on the scanning information obtained from channel feature scanning, assess the communication quality and link occupancy status of each channel; The target channel is determined based on the scanning results of all N channels in N consecutive transmission frames; Switch the working channel of the UAV communication device from the current working channel k to the target channel.

[0007] According to an embodiment of a first aspect of the present invention, a channel feature scan is performed on the scanned channel p within a channel scan time slot, comprising: The master end transmits an idle signal containing only a preamble symbol on the scanning channel p; In response to the preamble symbol sent by the master, the slave responds with an acknowledgment signal containing only the preamble symbol on the scanning channel p; During the idle period outside of the master sending idle signals and the slave responding to signals, the master and / or slave listen to and scan channel p to detect whether it is occupied by other UAV communication devices.

[0008] According to an embodiment of the first aspect of the present invention, evaluating the communication quality and link occupancy status of each channel includes: The preamble symbol of the acknowledgment signal received from the slave end by the master end is parsed to obtain the channel characteristics of the scanning channel p in order to evaluate its communication quality. The channel characteristics include signal energy and signal-to-noise ratio. Based on whether the master and / or slave ends detect preamble symbols sent by other drone communication devices during the idle period, it can be determined whether the scanning channel p is occupied by other links.

[0009] According to an embodiment of the first aspect of the present invention, evaluating the communication quality of each channel further includes: During idle periods, the master and / or slave ends collect noise information of the scanning channel p while listening to the scanning channel p. The communication quality of the scanning channel p is evaluated based on its channel characteristics and noise information.

[0010] According to an embodiment of the first aspect of the present invention, switching the operating channel of the UAV communication device from the current operating channel k to the target channel includes: After determining the target channel, the master end sends a switching command containing the target channel information to the slave end through the current working channel k in the first time slot of the next transmission frame; In response to the switching command sent by the master, the slave switches synchronously with the master to the target channel for data transmission in the first time slot of the next transmission frame.

[0011] According to an embodiment of the first aspect of the present invention, each time slot includes downlink time and uplink time; within the communication time slot, the downlink time and uplink time are dynamically allocated or pre-configured based on the asymmetry of uplink and downlink traffic on each UAV communication device.

[0012] According to an embodiment of the first aspect of the present invention, the data transmission method for UAV communication further includes an initial network access link establishment step, which includes: After the master unit is powered on, it periodically sends preamble symbols and network access information based on the initial channel or the default channel. The network access information includes the network access license number and the transmission frame number. After the slave device is powered on, it checks the preamble symbols sent from the master device one by one in N channels until it locks onto the channel where the master device is currently located, parses the network entry information sent by the master device, and establishes a communication link with the master device.

[0013] A second aspect of the present invention provides a data transmission device for unmanned aerial vehicle (UAV) communication, which is applied to a transmission system including one or more UAV communication devices, each UAV communication device being configured with a master end and a corresponding slave end. The data transmission device for UAV communication includes a time slot configuration module, a channel feature scanning module, a channel quality assessment module, a frequency selection module, and a switching module. The time slot configuration module is configured to divide a transmission frame containing M consecutive time slots into: the first M-1 time slots as communication time slots, and the Mth time slot as a channel scanning time slot; within the communication time slot, the UAV communication device performs bidirectional data transmission on the current working channel k, where k is an integer between 1 and N, and N represents the total number of selectable channels in the system. The channel feature scanning module is configured to switch the working channel of the UAV communication device to the scanning channel p and perform channel feature scanning on the scanning channel p within the channel scanning time slot; wherein the scanning channel p changes with the frame number of the transmission frame, scanning one channel per frame to cyclically traverse from 1 to N. The channel quality assessment module is configured to assess the communication quality and link occupancy status of each channel based on the scanning information obtained from the channel feature scanning. The frequency selection module is configured to determine the target channel based on the scanning results of all N channels in N consecutive transmission frames. The switching module switches the operating channel of the UAV communication device from the current operating channel k to the target channel.

[0014] According to an embodiment of a second aspect of the present invention, the channel feature scanning module performs a channel feature scan on the scanning channel p within a channel scanning time slot, the step of which includes: The master end transmits an idle signal containing only a preamble symbol on the scanning channel p; In response to the preamble symbol sent by the master, the slave responds with an acknowledgment signal containing only the preamble symbol on the scanning channel p; During the idle period outside of the master sending idle signals and the slave responding to signals, the master and / or slave listen to and scan channel p to detect whether it is occupied by other UAV communication devices.

[0015] A third aspect of the present invention also provides an unmanned aerial vehicle (UAV) communication system, which includes one or more UAV communication devices, each UAV communication device being equipped with a master terminal, a corresponding slave terminal, and the aforementioned data transmission device for UAV communication.

[0016] In summary, the data transmission method for UAV communication provided by this invention supports point-to-point network topologies and offers multiple selectable channels. It enables channel selection over a wide bandwidth range, thereby enhancing the system's anti-interference capability. Crucially, based on a time-division multiplexing architecture, this method achieves automatic switching to higher-quality channels by sequentially scanning each channel and evaluating its quality, dynamically optimizing the communication performance of bidirectional links. Furthermore, by monitoring each channel while scanning it, the method identifies the status of multiple links and actively avoids occupied channels during channel selection. This effectively prevents spectrum conflicts and network congestion that may occur during multi-UAV collaborative operations, thus supporting multi-UAV operation scenarios with multiple links coexisting in a single airspace.

[0017] To make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0018] Figure 1 The diagram shown is a flowchart of a data transmission method for UAV communication provided by an example of the present invention.

[0019] Figure 2 The diagram shows the time slots of the UAV communication system.

[0020] Figure 3 As shown Figure 1 A flowchart of step S20.

[0021] Figure 4 The diagram shown is a block diagram of a data transmission device for UAV communication provided in an embodiment of the present invention.

[0022] Figure 5 The diagram shown is a block diagram of a drone communication system provided in an embodiment of the present invention. Detailed Implementation

[0023] To address the problems existing in current Frequency Division Duplex (FDD) and Time Division Duplex (TDD) bidirectional links, this embodiment provides a data transmission method for UAV communication. This method is applied to a transmission system comprising one or more UAV communication devices, each UAV communication device being configured with a master end and a corresponding slave end. The data transmission method for UAV communication provided in this embodiment includes: Step S20: Divide the transmission frame containing M consecutive time slots into: the first M-1 time slots as communication time slots, and the Mth time slot as a channel scanning time slot; within the communication time slot, the UAV communication device performs bidirectional data transmission on the current working channel k. Here, k is an integer between 1 and N, and N represents the total number of selectable channels in the system.

[0024] Step S30: During the channel scanning time slot, switch the working channel of the UAV communication device to the scanning channel p and perform channel feature scanning on the scanning channel p; wherein, the scanning channel p changes with the frame number of the transmission frame, and scans one channel in each frame to cyclically traverse from 1 to N.

[0025] Step S40: Based on the scanning information obtained from the channel feature scan, evaluate the communication quality and link occupancy status of each channel.

[0026] Step S50: Determine the target channel based on the scanning results of all N channels in N consecutive transmission frames.

[0027] Step S60: Switch the working channel of the UAV communication device from the current working channel k to the target channel.

[0028] Figure 2 The diagram shows the system time slots. One period is one transmission frame, and each transmission frame contains M consecutive time slots. Each time slot has a length of T and includes an uplink time tu and a downlink time td. Step S20 configures time slots 1 to M-1 as communication time slots. Within communication time slots 1 to M-1, the master and slave ends perform bidirectional data transmission within the current working channel k. Specifically, within the uplink time tu of each communication time slot, the slave end sends an uplink signal to the master end, and the master end sends a downlink signal to the slave end within the downlink time td. In this embodiment, the uplink and downlink signals have the same format, both containing a preamble symbol and multiple data symbols. However, this invention does not limit this in any way. In other embodiments, the formats of the uplink and downlink signals may be different.

[0029] exist Figure 2In this transmission frame, the last time slot M of each transmission frame is configured as a channel scanning time slot. Within the channel scanning time slot, both the master and slave ends switch to the scanning channel p to perform a channel feature scan on p. The scanning channel p is an integer from 1 to N, and its value changes gradually with the frame number. For example, in the channel scanning time slot M of the first frame, the master and slave ends switch to channel 1 (which is now the scanning channel) and perform a feature scan on channel 1 to obtain its scanning information. In the communication time slots 1 to M-1 of the second frame, the master and slave ends continue bidirectional communication within their current working channel k. However, in time slot M of the second frame (i.e., the channel scanning time slot), the master and slave ends switch to channel 2 (which is now the scanning channel) and perform a feature scan on channel 2 to obtain its scanning information. In the channel scanning time slot of the third frame, the master and slave ends switch from their current working channel k to channel 3, which is now the scanning channel, to perform a feature scan on channel 3. Similarly, after the Nth frame, the master and slave ends will traverse all channels and perform feature scanning on all channels. Although this embodiment describes scanning channel p starting from channel 1 as an example, the present invention does not limit this in any way. In other embodiments, the scanning channel p can also be set to start from any channel within 1 to N; for example, starting from the i-th channel, the scanning order is i, i+1, i+2, ..., N, 1, 2, ... i-1, to complete the scanning of all channels.

[0030] In one implementation, step S30, which involves performing a channel feature scan on the scanning channel p within the channel scanning time slot M, includes: Step S301: The master end sends an idle signal containing only a preamble symbol on the scanning channel p.

[0031] Step S302: In response to the preamble symbol sent by the master end, the slave end scans channel p and responds with an acknowledgment signal containing only the preamble symbol.

[0032] Step S303: During the idle time period outside of the master end sending the idle signal and the slave end feeding back the response signal, the master end and / or the slave end listen to and scan the channel p to detect whether it is occupied by other UAV communication devices.

[0033] After obtaining the scanning information and monitoring results of scanning channel p in step S30, step S40 will evaluate the communication quality of scanning channel p based on the scanning information and determine whether scanning channel p is occupied based on the monitoring results. One implementation of step S40 includes: Step S401: Parse the preamble symbol of the acknowledgment signal received from the slave end by the master end to obtain the channel characteristics of the scanning channel p in order to evaluate its communication quality. The channel characteristics include signal energy and signal-to-noise ratio.

[0034] Step S402: Determine whether scanning channel p is occupied by other links based on whether the master and / or slave ends detect preamble symbols sent by other UAV communication devices during the idle period. In this embodiment, the master end is configured to monitor scanning channel p during the idle period; specifically, during the idle period, the master end remains in a receiving state. If it receives preamble symbols sent by slave ends of other UAV devices, it indicates that scanning channel p is occupied, and the communication system is currently in a multi-link coexistence state, that is, multiple sets of UAV devices are operating simultaneously.

[0035] To further improve the accuracy of channel feature scanning and evaluation, in another implementation, step S402 can be set to collect noise information of the scanning channel p, such as average noise and impulse noise, while monitoring the scanning channel p. Based on the noise information and the channel features obtained in step S401, the communication quality of the scanning channel is comprehensively evaluated.

[0036] Although this embodiment uses the master end's monitoring of the scanning channel as an example, the present invention does not limit this in any way. In other embodiments, the slave end can also be configured to monitor the scanning channel during idle time, and detect whether the scanning channel p is occupied by determining whether the slave end receives a preamble symbol sent from the master end of another UAV communication device.

[0037] After scanning all channels for N consecutive transmission frames, step S50 determines the target channel based on the communication quality and link occupancy status of each channel. Possible implementations of this step include: The process involves acquiring all unoccupied channels on the link to form a target channel set. This step removes occupied channels to avoid channel conflicts.

[0038] The communication quality of each channel within the target channel set is comprehensively evaluated. Specifically, considering the transmission distance, channels with signal energy higher than a set threshold are selected; then, based on the signal-to-noise ratio and noise information, the channel with the lowest noise is selected as the target channel. However, this invention does not impose any limitations on this process.

[0039] After determining the target channel, step S60 switches the operating channel of the UAV communication device from the current operating channel k to the target channel. One possible implementation of this step includes: Step S601: After determining the target channel, the master end sends a switching command containing the target channel information to the slave end through the current working channel k in the first time slot of the next transmission frame.

[0040] Step S602: In response to the switching instruction sent by the master end, the slave end synchronously switches to the target channel with the master end in the first time slot of the next transmission frame to perform data transmission.

[0041] Within the channel scanning time slot M of each transmission frame after switching to the target channel, the master and slave ends switch to scanning channel p again, repeating steps S30~S60, and start a new round of channel feature scanning, channel quality and link occupancy status assessment, determination of the next target channel, and switching.

[0042] Furthermore, in one possible implementation, the data transmission method for UAV communication also includes step S10, initial network access link establishment. This step includes: After the master unit is powered on, it periodically sends preamble symbols and network access information based on the initial channel or the default channel. The network access information includes information such as the network access license number and the transmission frame number.

[0043] After the slave device is powered on, it checks the preamble symbols sent from the master device one by one in N channels until it locks onto the channel where the master device is currently located, parses the network entry information sent by the master device, and establishes a communication link with the master device.

[0044] The data transmission method for UAV communication provided by this invention, based on the traditional TDD transmission architecture, configures the last time slot as a dedicated "channel scanning time slot." During this time slot, service data transmission is paused, and the system switches to a preset scanning channel to perform a feature scan to determine the communication quality and link occupancy status of the scanning channel. Through frame number cycling (p=1~N), a full scan of all N channels can be completed within N frame periods, achieving real-time, periodic awareness of the communication environment without affecting the continuity of normal communication. Furthermore, while scanning the inherent characteristics of the channel (signal energy, signal-to-noise ratio, noise level), the system also actively detects whether the scanning channel is occupied by other communication links through listening. After completing one round of full channel scanning, the "inherent channel quality" and "multi-link coexistence status" are jointly evaluated, and the channel with the best overall communication quality among the unoccupied channels is selected as the target channel. This setting allows multiple links to spontaneously and dynamically distribute themselves to different high-quality channels, achieving natural reuse of the spectrum space and greatly improving the overall communication capacity and reliability of the airspace.

[0045] like Figure 2As shown, in this embodiment, each time slot includes a downlink time tu and an uplink time td. Within the communication time slot, based on the asymmetry of uplink and downlink traffic on each UAV communication device, its downlink and uplink times are dynamically allocated or pre-configured. This setting can allocate more time slot resources for uplink data transmission than downlink data transmission according to the actual traffic demand, thereby achieving optimal resource allocation on a single frequency point and significantly improving spectrum utilization. Correspondingly, this embodiment also provides a data transmission device 103 for UAV communication, which is applied to a transmission system including one or more UAV communication devices, each UAV communication device being configured with a master end and a corresponding slave end. This data transmission device for UAV communication includes a time slot configuration module 20, a channel feature scanning module 30, a channel quality assessment module 40, a frequency selection module 50, and a switching module 60. The time slot configuration module 20 is configured to divide a transmission frame containing M consecutive time slots into: the first M-1 time slots as communication time slots, and the Mth time slot as a channel scanning time slot; within the communication time slot, the UAV communication device performs bidirectional data transmission on the current working channel k, where k is an integer between 1 and N, and N represents the total number of selectable channels in the system. The channel feature scanning module 30 is configured to switch the working channel of the UAV communication device to the scanning channel p and perform channel feature scanning on the scanning channel p within the channel scanning time slot; wherein, the scanning channel p changes with the frame number of the transmission frame, and one channel is scanned in each frame to cyclically traverse from 1 to N. The channel quality evaluation module 40 is configured to evaluate the communication quality and link occupancy status of each channel based on the scanning information obtained from the channel feature scanning. The frequency selection module 50 is configured to determine the target channel based on the scanning results of all N channels in N consecutive transmission frames. The switching module 60 switches the working channel of the UAV communication device from the current working channel k to the target channel.

[0046] In one possible implementation, the channel feature scanning module 30 performs a channel feature scan on the scanning channel p within the channel scanning time slot M. This step includes: Step S301: The master end sends an idle signal containing only a preamble symbol on the scanning channel p.

[0047] Step S302: In response to the preamble symbol sent by the master end, the slave end responds with an acknowledgment signal containing only the preamble symbol on the scanning channel p.

[0048] Step S303: During the idle time period outside of the master end sending the idle signal and the slave end feeding back the response signal, the master end and / or the slave end listen to and scan the channel p to detect whether it is occupied by other UAV communication devices.

[0049] In one feasible approach, the data transmission device for UAV communication also includes a network access module 10, which is configured to establish a link between the master and slave ends after they are powered on.

[0050] Since the data transmission device for UAV communication provided in this embodiment is different from the one described in the above embodiments... Figure 1 The device corresponding to the data transmission method for UAV communication described above, and the execution steps of each module within the device are all based on the same concept as in the above method embodiments. Therefore, steps S10 to S60 can be referred to above, and will not be repeated here.

[0051] Thirdly, this embodiment also provides a drone communication system, which includes one or more drone communication devices 100. Each drone communication device 100 is equipped with a master terminal 101, a corresponding slave terminal 102, and the aforementioned data transmission device 103 for drone communication. The various modules in the data transmission device 103 for drone communication can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the master terminal and / or the slave terminal, so that the processor in the master terminal and / or the processor in the slave terminal can call and execute the operations corresponding to each module. In this embodiment, the data transmission device 103 for drone communication is embedded in the master terminal 101.

[0052] In summary, the data transmission method for UAV communication provided by this invention supports point-to-point network topologies and offers multiple selectable channels. It enables channel selection over a wide bandwidth range, thereby enhancing the system's anti-interference capability. Crucially, based on a time-division multiplexing architecture, this method achieves automatic switching to higher-quality channels by sequentially scanning each channel and evaluating its quality, dynamically optimizing the communication performance of bidirectional links. Furthermore, by monitoring each channel while scanning it, the method identifies the status of multiple links and actively avoids occupied channels during channel selection. This effectively prevents spectrum conflicts and network congestion that may occur during multi-UAV collaborative operations, thus supporting multi-UAV operation scenarios with multiple links coexisting in a single airspace.

[0053] Although the present invention has been disclosed above by way of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of protection claimed in the claims.

Claims

1. A data transmission method for unmanned aerial vehicle (UAV) communication, characterized in that, A method applicable to a transmission system comprising one or more sets of UAV communication devices, each UAV communication device being configured with a master end and a corresponding slave end, the method comprising: The transmission frame containing M consecutive time slots is divided into: the first M-1 time slots are used as communication time slots, and the Mth time slot is used as a channel scanning time slot; within the communication time slot, the UAV communication device performs bidirectional data transmission on the current working channel k, where k is an integer between 1 and N, and N represents the total number of selectable channels in the system; During the channel scanning time slot, the working channel of the UAV communication device is switched to the scanning channel p and channel feature scanning is performed on the scanning channel p; wherein, the scanning channel p changes with the frame number of the transmission frame, and one channel is scanned in each frame to cyclically traverse from 1 to N; Based on the scanning information obtained from channel feature scanning, assess the communication quality and link occupancy status of each channel; The target channel is determined based on the scanning results of all N channels in N consecutive transmission frames; The working channel of the UAV communication device is switched from the current working channel k to the target channel.

2. The data transmission method for UAV communication according to claim 1, characterized in that, Within the channel scanning time slot, a channel feature scan is performed on the scanning channel p, including: The master terminal transmits an idle signal containing only a preamble symbol on the scanning channel p; In response to the preamble symbol sent by the master end, the slave end responds with an acknowledgment signal containing only the preamble symbol on the scanning channel p; During the idle time period outside of the idle signal sent by the master end and the response signal fed back by the slave end, the master end and / or the slave end listen to the scanning channel p to detect whether it is occupied by other UAV communication devices.

3. The data transmission method for UAV communication according to claim 2, characterized in that, The evaluation of the communication quality and link occupancy status of each channel includes: The preamble symbol of the acknowledgment signal received by the master end from the slave end is parsed to obtain the channel characteristics of the scanning channel p in order to evaluate its communication quality. The channel characteristics include signal energy and signal-to-noise ratio. Based on whether the master and / or slave ends detect preamble symbols sent by other UAV communication devices during the idle period, it is determined whether the scanning channel p is occupied by other links.

4. The data transmission method for UAV communication according to claim 3, characterized in that, The evaluation of the communication quality of each channel also includes: During the idle time period, the master end and / or the slave end collect noise information of the scanning channel p while listening to the scanning channel p; The communication quality is evaluated based on the channel characteristics of the scanning channel p and the noise information.

5. The data transmission method for UAV communication according to claim 1, characterized in that, Switching the operating channel of the UAV communication device from the current operating channel k to the target channel includes: After determining the target channel, the master end sends a switching command containing the target channel information to the slave end through the current working channel k in the first time slot of the next transmission frame; In response to the switching command sent by the master, the slave switches synchronously with the master to the target channel for data transmission in the first time slot of the next transmission frame.

6. The data transmission method for UAV communication according to claim 1, characterized in that, Each time slot includes downlink and uplink time; within a communication time slot, downlink and uplink time are dynamically allocated or pre-configured based on the asymmetry of uplink and downlink traffic on each UAV communication device.

7. The data transmission method for UAV communication according to claim 1, characterized in that, The data transmission method for UAV communication further includes an initial network connection link establishment step, which includes: After the master terminal is powered on, it periodically sends preamble symbols and network access information based on the initial channel or the default channel. The network access information includes the network access license number and the transmission frame number. After the slave device is powered on, it detects the preamble symbols sent from the master device one by one in N channels until it locks onto the channel where the master device is currently located, parses the network entry information sent by the master device, and establishes a communication link with the master device.

8. A data transmission device for unmanned aerial vehicle (UAV) communication, characterized in that, A transmission system comprising one or more sets of UAV communication equipment, each UAV communication equipment being configured with a master end and a corresponding slave end, the data transmission device for UAV communication includes: The time slot configuration module is configured to divide a transmission frame containing M consecutive time slots into: the first M-1 time slots as communication time slots, and the Mth time slot as a channel scanning time slot; within the communication time slot, the UAV communication device performs bidirectional data transmission on the current working channel k, where k is an integer between 1 and N, and N represents the total number of selectable channels in the system; The channel feature scanning module is configured to switch the working channel of the UAV communication device to the scanning channel p and perform channel feature scanning on the scanning channel p during the channel scanning time slot; wherein the scanning channel p changes with the frame number of the transmission frame, and one channel is scanned in each frame to cyclically traverse from 1 to N; The channel quality assessment module is configured to assess the communication quality and link occupancy status of each channel based on the scanning information obtained from channel feature scanning. The frequency selection module is configured to determine the target channel based on the scanning results of all N channels in N consecutive transmission frames; The switching module is configured to switch the working channel of the UAV communication device from the current working channel k to the target channel.

9. The data transmission device for UAV communication according to claim 8, characterized in that, The channel feature scanning module performs a channel feature scan on the scanning channel p within the channel scanning time slot. This step includes: The master terminal transmits an idle signal containing only a preamble symbol on the scanning channel p; In response to the preamble symbol sent by the master end, the slave end responds with an acknowledgment signal containing only the preamble symbol on the scanning channel p; During the idle time period outside of the idle signal sent by the master end and the response signal fed back by the slave end, the master end and / or the slave end listen to the scanning channel p to detect whether it is occupied by other UAV communication devices.

10. A drone communication system, characterized in that, It includes one or more sets of UAV communication equipment, each UAV communication equipment being equipped with a master end, a corresponding slave end, and a data transmission device for UAV communication as described in claim 8.

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